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Recent 1981 yz465 purchase

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Hi all new to the site and read a few threads kinda new to the dirt bike scene but really enjoying it I recently picked up a yz465 and love the bike of course with age comes repairs that got neglected over the years but it does run and move on its own power so that's a big plus and power it does have very hard to keep that front tire down in any gear lol its a rush

I'll post some pics when I get a chance this weekend as I'll be doing a few things to get it running a bit smoother carb needs to be totally gone through tank cleaned as well, oil changed, new air filter and whatever else I can think of when I get to that point so if any one has had one of these bad boys and can give me any tips to keep her in optimum running shape would be greatly appreciated like what kind of oil to use in the clutch case and pre mix you use with the best oil also any tips for the carb on jetting its got the 2 stroke blubber from closed throttle to about half before it cleans up I am going to clean the carb and maybe that's all I need but if I need jets which ones should I get if needed I'm pretty sure it's all stock not even sure if the previous owner changed the top end I'm the third owner of this bike previous owner said it's broken an ankle on the owner before him that's why he got rid of it lol I don't find it to bad to kick and I'm not a big guy

Once I get it up and purring I'll post a couple vids and you guys can tell me if she sounds good I do know it's very loud is there a way too repack the original silencer on those

Like I said any help is appreciated

 

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Congrats on the new bike! I've got the same issue with my bike, WAY too loud. It doesn't have the original muffler, it's got an old supertrapp. Ive been told to ditch it and get a new one, but I don't think that would apply in your situation since yours is original. I think you can buy generic 2 stroke packing and just repack with that. You just have to figure out how to take apart your muffler.

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Any used bike especially a 35+ year old bike will need so attention. Those old yz465 are worth fixing up, they were good bikes and still are. 

Let see if I can give you some help.

Check the carburetor,  look to see what its has for jets and if it clean. Sorry i dont have the exact jetting specs for that bike hopefully someone esle does or you can find it online.  Do a compression test those YZs should be 150lbs plus if its under 120 then its probably time for a top end. Take a look at the reeds make sure there not broken or chipped. Get a new spark plug probably a ngk br8es .

Then there is  fuel and oil. In 1981 gas was a lot better quality.  Try to find some 92+ octane ethanol free gas and mix at 24:1. With modern oils you could run 32 or 40:1 but the bike was jetted for more oil. If the gas is old or low octane it will run like 

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Ok I'll ask this weekend at the shop about the packing and give it a try

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I'm pulling the carb this weekend and going through it total clean I'll check what the jets are in it I also ordered some pilot jets to be safe as it idled rough and didn't pull to hard from closed to half throttle just the blubber but cleaned out after half throttle I got a 35 40 and 45 pilot to be sure and who knows it might just be a really dirty carb as it sat for a long time

Thanks for the help much appreciated photos to come Fri

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Also would like any info on a download on a manual for the bike with specs especially if I got to take the top end off to rebuild

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1 minute ago, Mr454 said:

Also would like any info on a download on a manual for the bike with specs especially if I got to take the top end off to rebuild

Can you repack that silencer or is it welded all around?  Had a 80' rm400 couple months ago that was stock welded . But Idk if Yamaha was then also.  Awesome bike tho man:thumbsup: gotta let us see it :rolleyes:

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7 hours ago, Mr454 said:

 

Hi all new to the site and read a few threads kinda new to the dirt bike scene but really enjoying it I recently picked up a yz465 and love the bike of course with age comes repairs that got neglected over the years but it does run and move on its own power so that's a big plus and power it does have very hard to keep that front tire down in any gear lol its a rush

I'll post some pics when I get a chance this weekend as I'll be doing a few things to get it running a bit smoother carb needs to be totally gone through tank cleaned as well, oil changed, new air filter and whatever else I can think of when I get to that point so if any one has had one of these bad boys and can give me any tips to keep her in optimum running shape would be greatly appreciated like what kind of oil to use in the clutch case and pre mix you use with the best oil also any tips for the carb on jetting its got the 2 stroke blubber from closed throttle to about half before it cleans up I am going to clean the carb and maybe that's all I need but if I need jets which ones should I get if needed I'm pretty sure it's all stock not even sure if the previous owner changed the top end I'm the third owner of this bike previous owner said it's broken an ankle on the owner before him that's why he got rid of it lol I don't find it to bad to kick and I'm not a big guy

Once I get it up and purring I'll post a couple vids and you guys can tell me if she sounds good I do know it's very loud is there a way too repack the original silencer on those

Like I said any help is appreciated

 

 

Where to begin. ?  The blubber from "closed throttle to about half" is most likely caused by the varnish built up in your carb jets.  Cleaning that thing out is the first step.  #2, drain whatever gas and oil mixture was in the gas tank out and dispose of it responsibly.  Since that bike has a plastic gas tank I would slosh 1/4 of a gallon of gas around in it to clean it out and dispose of that responsibly as well.  Pull the petcock assembly out of the fuel tank and make sure that any filter screens are clear and free flowing

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Not sure if it's welded its at the father in laws right now but this Fri I'll be tearing into it

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Ok that will be first on the list carb and tank the pet cock is a mother to open and close to

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While you got the petcock apart check the o-ring in it as well. I always replace em on my old bikes. That usually will fix any, drips, leaks, and other stuff

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Will do its not leaking at the moment but better safe the sorry later

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Tried the link but wouldn't give me the year I need

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I'm pretty sure the YZ-465 silencer is not serviceable with out a welding torch.

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Well I'll have to look for an aftermarket one I guess any good suggestions for these bikes what works best

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I'll have to leave that to the rest of the experts as I never modified my 1977 YZ-250D

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Not looking for any horsepower gain it's got enough of that just something to not scare the dead lol

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If the silencer is stock its not serviceable. DG makes repackable ones. Did some research 45 is the stock pilot, 390 is the main.

I dont have a yz manual but i do have one for a 81 it465 there could be some useful info i can send a digital copy if you want.

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Now that is what makes Thumper Talk great!  Stepping up and trying to help!

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